The spokesman claimed that "foreigners regularly travelled to Ukraine, but not in order to accompany [the IRC on] humanitarian missions".

"Foreign employees established contact with officials in DPR ministries and agencies, showing interest in obtaining information about the situation in the republic," he said.

He also accused the agency of "hiring DPR citizens for work without signing agreements with them, evading the payment of taxes into the DPR budget".

IRC says its mission is to help people whose lives have been shattered by conflict and disaster, and says its humanitarian work in eastern Ukraine includes the provision of women's hygiene and safety equipment.

Heavily armed rebels have been fighting government forces for a year in Ukraine's Donetsk and Luhansk regions.

The West says Russia has armed the rebels and sent in regular soldiers - an accusation echoed by independent experts.

Moscow insists that any Russians on the rebel side are volunteers.

Separately, Russia has criticised French President Francois Hollande and German Chancellor Angela Merkel for their decision to boycott a World War Two victory parade on 9 May in Moscow because of their misgivings over Russia's actions in Ukraine.

"I think it's an ill-considered decision that contradicts the interests of both France and Germany," Culture Minister Vladimir Medinsky was quoted by the AFP news agency as saying on Wednesday.